This invention relates in general to skive fingers for fuser apparatus of reproduction equipment, and more particularly to reproduction equipment fuser apparatus skives which have capillary micro-grooves to substantially prevent build up of image-degrading fluid on the fuser apparatus skive fingers.
In typical commercial reproduction equipment (electrostatographic copier/duplicators, printers, or the like), a latent image charge pattern is formed on a uniformly charged dielectric member. Pigmented marking particles are attracted to the latent image charge pattern to develop such image on the dielectric member. A receiver member is then brought into contact with the dielectric member. An electric field, such as provided by a corona charger or an electrically biased roller, is applied to transfer the marking particle developed image to the receiver member from the dielectric member. After transfer, the receiver member bearing the transferred image is separated from the dielectric member and transported away from the dielectric member to a fuser apparatus at a downstream location. There the image is fixed to the receiver member by heat and/or pressure from the fuser apparatus to form a permanent reproduction on the receiver member.
One type of fuser apparatus, utilized in typical reproduction apparatus, includes at least one heated roller and at least one pressure roller in nip relation with the heated roller. The fuser apparatus rollers are rotated to transport a receiver member, bearing a marking particle image, through the nip between the rollers. The pigmented marking particles of the transferred image on the surface of the receiver member soften and become tacky in the heat applied in the roller nip. Under the pressure in the nip, the softened tacky marking particles attach to each other and are partially imbibed into the interstices of the fibers at the surface of the receiver member. Accordingly, upon cooling, the marking particle image is permanently fixed to the receiver member.
It sometimes happens that the marking particles stick to the peripheral surface of the heated roller and result in the receiver member adhering to such roller; or the marking particles may stick to the heated roller and subsequently transfer to the peripheral surface of the pressure roller resulting in a receiver member adhering to the pressure roller. It has therefore been a general practice to apply a release oil coating to elements of the fuser apparatus (e.g., the fuser roller and/or pressure roller). The release oil is selected to have properties, well known in the prior art, which will inhibit the sticking of marking particles to the fuser apparatus elements. However, the release oil is not completely effective in preventing receiver members from adhering to the fuser apparatus elements.
In view of the receiver member adherence problem, a skive mechanism, including mechanical skive fingers or separator pawls for example, has been employed to engage the respective peripheral surfaces of the fuser apparatus rollers to strip any adhering receiver member from the rollers in order to substantially prevent receiver member jams in the fuser apparatus. Typically a fuser apparatus skive mechanism includes a plurality of skive fingers. The skive fingers are generally formed as elongated members respectively having a relatively sharp leading edge urged into engagement with a fuser apparatus roller. For example, the skive fingers may be thin, relatively flexible, metal shim stock. The respective leading edge of each of the skive fingers is directed in the opposite direction to rotation of the fuser apparatus roller with which such skive finger is associated so as to act like a chisel to strip any receiver member adhering to such roller from the peripheral surface thereof.
Skive fingers, oriented as described, as currently found in exemplary fuser apparatus, have a tendency during operation of the reproduction equipment to become wetted with fuser release oil that accumulates on the fingers during the fusing process. The receiver members, bearing images to be reproduced, as they are released from the fuser, will come in contact with skive fingers as they are guided away from the fuser apparatus. The accumulated release oil then becomes wetted to the receiver members during such contact, and the oil is transported back through the elements of the reproduction equipment, particularly when the receiver member is recirculated for forming a duplex reproduction. Some of release oil is then transferred from the receiver members onto the reproduction equipment elements, and may then potentially cause undesirable image defects on subsequently reproduced images.
In view of the above, this invention is directed to a fuser apparatus, for example having a pair of rollers in nip relation to transport a receiver member therebetween to permanently fix a marking particle image to such receiver member, a skive mechanism for stripping a receiver member adhering to a fuser apparatus roller from the roller, and a mechanism for applying a release oil to the fuser rollers. The skive mechanism includes a plurality of skive fingers formed as elongated, thin, flexible members located so as to engage the fuser apparatus rollers in a manner so as to substantially prevent damage to such associated fuser apparatus rollers. Each of the skive fingers have capillary micro-grooves formed therein for the purpose of channeling release oil away from the respective skive finger tips, thereby substantially eliminating image degradation by build up of the release oil.
The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiment presented below.